Dual radiant heater



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Feb. 6, 1962 M. K. MURPHY DUAL RADIANT HEATER 50,/ s/IFI 1%60 62 38 se v4 F 48 s4 'a Jj 4 64? 4 70 52 f JNVENTOR.

MAXWELL K. MURPHY.

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3,020,384'- DUAL RA-DINT HEATER; f

Maxwell K. Murphy, 535 W. Goldengate, Detroit, Mich. e

Filed Apr. 20,,1959,-Ser.1No. 807,355

7 Claims. (Cl. 219-39) This invention relates to .electric heating devices and particularly to a wall mounted combined convection and` be completely ott for most of' the day, yuser complaints are4 common. Furthermore, it appears thata forced current of warmedconvection` air satisfies a physiological demand on the part of most people which radiant heat does not meet, at least during the initialwarmup period.

Electric radiant heaters of the glass or porcelainized sheet type havel proven exceptionally satisfactory for panel type heating because'of their excellent radiating capacity and'economy. These `sheet* type elements provide considerable radiationA or leakage from the back side, which emitted heatis usually reiiected toward the element by a metaly reiiector to increase radiating eiiiciency.

Itis theobiect of my inventiorrto provide an `improved dual combined radiant and convection heater utilizing sheet type elements which is suitable for heating two rooms of a house with economy of construction and operation, andl economy of wallspace.

For a preferred embodiment of my invention, reference` is made to the iacoompfanying'drawings, in whichI reference characters have been used to dmignate like partsreferred toherein.

In the drawings:

FIG. 1 is a front elevation of my dual heater, the rear elevation being yan exact duplicate; f

FIG. 2 is an enlarged Vertical section taken as indicated by the linek 2f-2 on- FIGJ FIG. 3' is an enlarged fragmentary section of one ofthe heating elements taken on line 3 3 of FIG. 1; and

FIG; 4' isa schematic Wiring diagram ofv the heater control circuit.

Referring to the'drawings, it may be seen that' my improved heater comprises acasing of metal, Fiberglas or the like. The casing has oppositely disposed sidewalls,

top and bottom walls as shown, :and front and back' Walls provided with large area openingsv for reception of the heating elements 12, 14".

Oppositely disposed air intake conduits' 156; 18m-redisposed at the top of the assembly, and at the bottom the casing is provided With oppositely facing air outlet registers 20, 22. The latter are provided' with movable vanes or shutters which are adjustable by knobs 24, 26,. so that one or the other'maybe closed" when desired.

The entire assembly is' of' such width-approximately 15j inchesthat it will iit between the joistsV of a building, which joistsare usually* spaced 16 inches" apart in accord'- ance 'with standard building codes.

The assembly isof'such' width that ,theheatingelements 12,* 14, willu beu substantially liush with oppositely facing.V

wallj surfacesk ofV adjoining'rooms' ofy a house or building' with the intakes 16, 18, and outlet registers. 20, 22;. protruding slightly.

The heating elements'1'2, 1'4, are of' sheet form andare secured in the casing 10, in any suitable manner, such as n flanges 2S. The elements may be of the glass type, such as those widely sold under the trade name Glassheah or they may be of the porcelainized metal type. Referring to FIG. 3, it may be seen that the element 12 comprises a steel sheet 30 having a coating 30, 32, of vitreous material on each surface thereof. Adhered or fused to the 2 rear surface coating 34 is a resistor 3'6 of aluminum alloy or other metal. The latter is' preferably in the form of a grid, and if desired', a protective coating of silicone varnish 0r' other heat resistant material may be applied over the' resistor grid toinhibit corrosion.

For other examples of heating elements suitable for use 1in the device being' described', reference is made to Glynn Patent Number 2,622,178, Gai-away Patent Numbe1"2`,859,32l, Knoll Patent Number 2,795,682,1and to my copending application Serial No. 715,604, filed February 17, 1958. y y

Application of a voltagey across the'resistor of the elementwill heat the element, and heat rays, most of'which' are in the infra-redrange of the spectrum, will be radiated yfrom thel front surface'of the element. The oppositely disposed rear surface of the other heating elementwill act as a reflector of heat raysemitted from the yrearsurfaces of the` two elements `and thus the radiating efficiency of the elements is increased. v

While most of the heat' generated will ybe radiated di'- rectlyinto the rooms in which the elements 12 and 14 face, there will"beconsiderabllev heat emit/ted into the' interior of the casing which heat, in they absence of any air propelling means, will` iiow out of the; heater intakes 16 and 1S through thechirnney effect produced by air entering lthe registers 2li, 22, and help heat the space by convection. y y

Because heat tends to'rise' and toincrease the overall heating efficiency of the device, Il prefer to admit air to the interior ofthe casing' behind the heating elements at the top and to force lthe heated air' out at the'bottom. To accomplish this, `a blower assembly isf provided which comprisesa motor 38-and a` blad'ed rotor 4d. tom, baffles 42, 4d', are disposed'suehfthat air drawn in at: the top1 through intakes 16, 158', will be heated and expelled throughtheregisters 20, 22, at the bottom: The intensityy of the air current may be reducedinfone room and correspondingly increased inthe other by proper adjustment lof theregistertlouvr'es by means of knobs 2'4; 26. In some instances, where one` of the rooms is relatively small (a bathroom, for' example), the' bafeslZ, 44, may be disposed eccentrically to providek a" permanent unequalv The heater mayv be energized vfrom a*v standard households 11I5, 208i* or 240? Volt' `line, an'd the elements and' blower may be connectedin'parallel'suchfthat the blower' operates whenever the elements are energized? to= thereby providel a combination of` radiant and? convection heat'.

From'the standpoint of economy, it is preferable, howeven. that a dilerential typel off thermostat be used which will energize' the blower and the heater elements at some1 selected temperature, say 68 F., and rwhen'roomL ternperature has risen to 70 or 72 F., the blower willfcutfout leaving theeiements 12,14; energizedl tol continue heating .by radiation: until;l the? temperature rises to' some selected maxi umfsayl F., whereupon the 'elements1'12", 154,

winyre on and oir to maimaiitdesirea.comfort by radiyation alone.-y 'Fhis systemprovide's quickl warmup? of; a

coldf room by a combination of convection-v and'v radiant heatcthen continues to maintain comfortable temperaturev by radiation"` alone. Stich1 a control? system is described and claimed in my copending application Serial No. 771,- 604, tiled November 3, 1958, now Patent No. 2,978,568, granted April 4, 1961.

The present arrangement is adapted to a different type At the botn o'f control which greatly enhances the utility of the heater and improves the economy of operation thereof. Reference is made to FIG. 4 which shows a schematic circuit for controlling the heater.

In this arrangement, the heating elements 12 and 14 are fabricated for normal operation at (for example) 110 volts. The input circuit from the main supply is a three wire circuit with (for example) either 208 volts or 230 volts between outside conductors 46, 48.. The voltage between conductors 46-50 and 11S- 50, is 110.

The differential thermostat 52 is connected in the secondary circuit of a transformer 54 and controls energization of relay coils 56, 58, which coils when energized, close switches 60, 62, respectively.

When the thermostat 52 calls for heat at low setting, it will energize relay coil 58 through leads 64, 66, `68, to close switch 62. Switch 60 remains open. Closure of switch 62 will energize elements 12, 14, through leads 46, 70 and 48, and thus subject the elements to the higher voltage existing across leads 46, 48. At the same time, motor 38 will be energized through leads 50, '72, 74 and 48. Application of overvoltage to the heating elements 12, 14, will provide extremely quick warmup of these elements with consequent rapid warming of the heated space by a combination of convection and radiation. Because the heating elements are designed for normal operation at lower voltage, the overvoltage will cause failure of the elements by burnout unless the heat is removed from the element With suicient rapidity to prevent overheating of the resistor grids. This is readily accomplished by the blower 40, which of course must be chosen of suicient capacity to perform this function.

As soon as the temperature of the heated spaces rises to preset minimum, thermostat 52 will denergize coil 58 and energize coil 56. The blower will cease operation and the high voltage circuit to the heating elements will be opened. At the same time, switch 60 will close connecting elements 12, 14, to the low voltage supply through leads S0, 76, 78 and 46. The heater element, now thoroughly warm, will continue to heat by radiation with some convection currents owing in reverse direction through the casing 10. When the thermostat 52 reaches its maximum setting, it will de-energize coil 56 and will continue to cycle this coil to maintain comfort unless there is a rapid drop in room temperature whereupon the coil 58 will be again energized.

By subjecting the heating elements to overvoltage, rapid warmup of the elements with consequent rapid warmup of the space is achieved. In addition, a blast of warm air is circulated in the space. This feature appears to nullify complaints of users with respect to slow response by electric radiant heaters, and seems to satisfy a physiological demand of persons who associate an adequate heating system wth a blast of hot air.

Once the forced convection air has warmed up the space, the cycling of the heating elements at normal voltage with substantially total radiant emission will maintain comfort with excellent economy.

It Will be thus seen that I have provided an improved heating appliance which supplies both convection and radiant heat to adjoining rooms with economy of construction and operation, and with extreme compactness and economy of wall space.

I claim:

1. In a combination radiant and convection heater adapted for installation in a common wall between adjacent rooms, a pair of sheet type electric radiant heating elements having resistor grids adhered to their respective inner surfaces mounted back-to-back in spaced relation for emitting heat rays from their respective outer surfaces directly into said rooms, a pair of oppositely disposed air inlets mounted above said heating elements, a pair of oppositely disposed air outlets mounted below said heating elements, and a blower mounted in the heater operable to provide forced air circulation through said heater yfrom said inlets and out through said outlets thereby to provide convection currents of heated air from the rear surfaces of said elements in both rooms.

2. The combination of claim l including a baie mounted below said elements and adjacent said outlets for directing the air currents outwardly in opposite directions.

3. The combination of claim 1 including adjustable louver means in each outlet for varying the ow of air into each room.

4. The combination of claim 1 including heat responsive control means for controlling energization of said elements and said blower operable to energize said blower and simultaneously connect said heating elements across a relatively high voltage supply in response to selected temperature condition prevailing in said rooms, and to deenergize said blower and connect said elements across a lower voltage supply in response to attainment of a second temperature condition in said rooms.

5. In combination with a wall mounted heater for heating adjoining rooms simultaneously, a pair of electric radiant heating plates having resistor grids adhered to their respective inner surfaces, said plates being mounted in spaced oppositely facing relation with their respective heat emitting outer surfaces exposed to said rooms, means for withdrawing air from said rooms and for forcing said air through the space betweensaid plates and out into said room-s thereby to provide forced convection heating of said rooms to augment the radiant emission from said plates.

6. In combination with a wall mounted heater for heating adjoining rooms simultaneously, a pair of electric radiant heating plates having resistor grids adhered to their respective inner surfaces, said plates being mounted in spaced oppositely facing relation with their radiating outer surfaces exposed to said rooms, means for forcing a current of air from said rooms through the space between said plates and out into said rooms thereby to provide forced convection heating of said rooms to augment the radiant emission from said plates, thermostat means for controlling said heater including means for simultaneously energizing said heating elements and said air current forcing means at selected temperature thereby to provide combination radiant and convection heating of said rooms, and means for cutting oi operation of said forcing means at selected higher temperature thereby to provide radiant heating only.

7. The combination set forth in claim 6 wherein said heating elements are energized at higher than normal operating voltage during the period of combined radiant and convection heating,

References Cited in the tile of this patent UNITED STATES PATENTS 1,071,716 Dickinson Sept. 2, 1913 1,295,416 Berry Feb. 25, 1919 1,539,734 Hauber May 26, 1925 1,671,568 Barker May 29, 1928 1,888,497 Gasch Nov. 22, 1932 2,065,760 Smith Dec. 29, 1936 2,176,586 Goerg Oct. 17, 1939 2,205,001 Timmis June 18, 1940 2,226,061 Kershaw Dec. 24, 1940 2,471,784 Seifner May 31, 1949 2,724,044 Campbell Nov. 15, 1955 FOREIGN PATENTS 627,865 Great Britain Aug. 19, 1949 

